This invention generally relates to network management systems, and more particularly to a network management system having more than one network management work station with at least one of which being used as a backup management work station that may remotely communicate with a main network management station.
In selecting a specific type of computer system for a network management system, reliability is a key concern.
Usually, a smaller computer system, such as SUN Sparc work station, HP 3000 work station or AT&T GIS 3350 work station, is less reliable than a larger computer system, such as HP 9000 computer or IBM 3090 computer, because a smaller computer system may lack built-in redundancy features.
To enhance the reliability when small computers are used, network management systems store data in Redundant Array Inexpensive Disks (RAID), where several inexpensive disks contain the same data and operate in parallel fashion. In operation, even if one or more inexpensive disks fail, the network management systems can still properly function.
To further enhance the reliability, more than one network management station can be connected to the RAID.
FIG. 1 depicts a network management system including work stations 102 and 104, RAID 118, and front-end processor 122. Work stations 102 and 104 are connected to RAID 118 and front-end processor 112. Terminals 1-n are connected to network 126 and able to send data packets to station 102 or 104 via front-end Processor 122. Work station 102 or 104 can receive and store incoming data packets into RAID 118.
In operation, work station 102 can be chosen to serve as a main network management station, and work station 104 as a backup network management work station. When work station 102 is in proper operational condition to receive the incoming data packets containing network management information, it is not desirable for station 104 to receive the same incoming data packets, since the network management system requires only a single control station to collect and store the necessary network management information. Thus, front-end processor 122 can be used to direct incoming data packets containing network management information from network 126 to work station 102 when the station is in proper operational condition. Front-end processor 122 switches the incoming data packets containing network management information to work station 104 when work station 102 fails. By using work station 102 as the backup network management station, the reliability of the network management system is improved.
One disadvantage of the scheme shown in FIG. 1 is that a front-end processor is needed, which can be relatively expensive. For example, the current price of a typical front-end processor IBM 3780 is around 100 thousand US dollars.
Another disadvantage of the scheme shown in FIG. 1 is that each of the incoming data packets containing network management information has to be switched by the front-end processor, thus slowing data transmission speed.
The invention reflected in U.S. Pat. No. 5,661,719, filed on Oct. 19, 1995 and entitled METHOD FOR ACTIVATING A BACKUP NETWORK MANAGEMENT STATION IN A NETWORK MANAGEMENT SYSTEM, can overcome these two disadvantages. Applicants incorporate this patent into the present application by reference.
FIG. 2 depicts a network management system (200) that can overcome the two disadvantages in the scheme shown in FIG. 1.
As shown in FIG. 2, the network management system includes work station 202 (chosen as a main network management station) and work station 204 (chosen as a backup network management station). Being both connected to RAID 218, work stations 202 and 204 can both get access to RAID 218. The data packets from terminals 1-n can be simultaneously delivered to work stations 202 and 204 via link 224.
When work station 202 is in proper operational condition, work station 204 is set in an inactive mode. Thus, even the data packets from Terminals 1-n are simultaneously delivered to work stations 202 and 204 via network 326, only work station 202 acts upon the incoming data packets with the IP and MAC addresses matching these assigned to work station 202.
When work station 202 is about to fail, a fault condition signal is sent from work station 202 to work station 204 via physical link 206. The fault condition signal invokes a routine (which can be stored in station 204) to set network management station 204 in an active mode. Thus, after work station 202 has failed, work station 204 will act upon the incoming data packets with the IP and MAC addresses matching these that have been assigned to station 202.
One disadvantage in the scheme shown in FIG. 2 is that there requires a physical link between the main network management station and the backup network management station. Especially when the two network management stations are located in two remote sites, the physical link may entail a substantial cost for installation and materials.
Therefore, there has been a need to provide a reliable network management system with reduced cost and improved speed.